The present invention relates to an automatic bending system which includes an automatic bending press including a pair of cooperating bending tools, and an automatic manipulator including a head movable in a work space and provided with a toolholder intended to receive at least two take-up members independent from each other.
In a conventional bending system of this type, the manipulator is programmed for supplying pieces of sheet metal to the bending press, for holding and moving the pieces during the bending cycles and for releasing the pieces at the end of the bending cycles. The bending cycle of a piece of sheet metal generally comprises the step of picking-up the single sheets from a pack in which the sheets are vertically staked. In the vast majority of cases, a take-up member with aspirating suckers is used for carrying out this operation. Any other type of take-up member would render extremely more complex the pick-up of a single sheet from a pack. The take-up members with aspirating suckers often are not suitable for holding the sheets during the bending cycles, especially when the pieces are small, when they must be held by the take-up member along an edge or when the resiliency of the suckers would prevent reaching the desired precision of positioning of the piece.
For this reason, manipulators for automatic bending systems having a head provided with two independent take-up members, formed for instance by a take-up member with aspirating suckers and by a gripper, have already been produced. One of the problems which can arise when two or more take-up members placed on the same head are used is the risks that such take-up member may interfere with each other or with other parts of the manipulator or of the bending press during the operation.
Furthermore, known manipulators of this type comprise a first motor dedicated to controlling the rotation of the head and a second motor dedicated to controlling the rotation of the toolholder. This solution does not allow to take maximum advantage of the available capacity of the motors, especially when the working program of the manipulator does not provide for the contemporaneous use of the first and second axis.
An object of the present invention is to provide a bending system of the type defined at the beginning of the description which has a simple and compact structure, which attains the maximum freedom of movement and which avoids interference with the take-up members.
Another object of the present invention is to provide a manipulator of the type specified above, which permits to exploit in the best possible way the capacity of the motors and which, remaining the same the other conditions, enables the use of smaller and less expensive motors.
According to the present invention, this object is achieved by a bending system comprising: an automatic bending press (46) including a pair of bending tools (48, 50) cooperating which each other, and an automatic manipulator (10) including a head (26) movable in a work space and provided with a toolholder member (29) intended to receive at least two take-up members (32, 34, 38, 42) independent from each other, characterised in that the head (26) is rotatable about a first axis (28) and that the toolholder member (29) is provided with two tool attachment seats (30) arranged on opposite sides of said first axis and rotatable about a common second axis (36) orthogonal to the first axis (28).
According to the present invention, this object is achieved by a manipulator of the type specified above, characterised in that the head is inserted in an epicycloidal gearing including: two tootheaded input members, each of which is rotatable about an axis which is fixed with respect to the arm, the two tootheaded members being driven in rotation independently from each other by respective motors, and at least one planet gear rotatably carried by the head about said second axis and rotatably connected to said toolholder, and wherein the head forms the planet-carrier of said epicycloidal gearing.
By virtue of the above solution, the power of both motors can be used for moving either the head or the toolholder, or can be split between the head and the toolholder. With respect to the case in which each motor is dedicated to a respective axis, the solution according to the present invention enables the capacity of the motors to be halved, without changing the power available on each axis when they are driven singularly. In addition, the particular disposition of the gear support members and load-bearing parts, enables manufacturing of a particularly compact head and particularly adapted to permit the connection of two different take-up tools which can be operated independently.